version 6.0

4th Dimension supports two logical operators that work on Boolean expressions: conjunction (AND) and inclusive disjunction (OR). A logical AND returns TRUE if both expressions are TRUE. A logical OR returns TRUE if at least one of the expressions is TRUE.

4th Dimension also provides the Boolean functions `True`, `False`, and `Not`. For more information, see the descriptions of these commands.

The following table shows the logical operators:

Operation | Syntax | Returns | Expression | Value |

AND | Boolean & Boolean | Boolean | ("A" = "A") & (15 # 3) | True |

("A" = "B") & (15 # 3) | False | |||

("A" = "B") & (15 = 3) | False | |||

OR | Boolean | Boolean | Boolean | ("A" = "A") | (15 # 3) | True |

("A" = "B") | (15 # 3) | True | |||

("A" = "B") | (15 = 3) | False |

The following is the truth table for the AND logical operator:

Expr1 | Expr2 | Expr1 & Expr2 |

True | True | True |

True | False | False |

False | True | False |

False | False | False |

The following is the truth table for the OR logical operator:

Expr1 | Expr2 | Expr1 | Expr2 |

True | True | True |

True | False | True |

False | True | True |

False | False | False |

Tip

If you need to calculate the exclusive disjunction between Expr1 and Expr2, evaluate:

(Expr1 | Expr2) &Not(Expr1 & Expr2)

See Also

Bitwise Operators, Comparison Operators, Date Operators, Numeric Operators, Operators, Picture Operators, String Operators, Time Operators.